The present invention relates to multi-ply braiding apparatus and, more particularly, to a circular braiding apparatus wherein a matrix of fiber carriers are arranged in a cylindrical configuration.
The process of braiding is distinguished from weaving in that all fibers are interchanged (moved) in a braiding cycle while in weaving only a single fiber (the fill) is moved through a fixed array of fibers (the warp). Multi-ply braiding is distinguished from conventional braiding in that more than two layers (plys) are formed by the process.
Any braiding process is characterized by the fact of all fiber carriers being in motion resulting in intertwined fibers. Multi-ply braiding machines use a matrix array of carriers capable of alternate row and column position shifts. Reversal of the direction of row and column motion during a complete shift cycle produces the intertwining of fibers. Production of complex shapes is possible by adjusting the length of travel (number of spaces shifted) of each row or column.
Multi-ply braiding concepts and machines are disclosed in the patents to Bluck U.S. Pat. No. 3,426,804 and Florentine U.S. Pat. No. 4,312,261. In the Bluck and Florentine patents, the teachings of which are incorporated herein by reference, each row and column consists of discrete eyelets or carrier blocks. In other machines presently in use, row motion is accomplished by shifting grooved track members containing fiber carriers. Column motion consists of shifting the discrete fiber carriers. In circular concepts, row motion is accomplished by shifting concentric rings or track members, as shown in FIG. 6 of the Florentine patent. Column (radial) motion again consists of shifting discrete carriers.
In circular braiding machines, it is difficult and expensive to produce concentric rings of necessarily different diameters which fit properly together. Also, it is necessary to keep an inventory of many rings of different sizes for the replacement of rings that may be damaged in use. In addition, the capacity of the machine as measured by the number of rings cannot be easily expanded. A flat circular braiding machine having a large number of concentric rings is burdensome in that it requires a large amount of space and it is difficult to shift the carriers radially through a large number of rings without jamming taking place.
Accordingly, a need has arisen for a new and improved braiding apparatus of the circular type having interchangeable rings of the same diameters. This need is filled by the cylindrical braiding apparatus of the present invention.